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In this study, plant growth-promoting potential isolates from rhizosphere of 10 weed species grown in heavy metal-contaminated areas were identified and their effect on growth, antioxidant enzymes, and cadmium (Cd) uptake in Arundo donax L. was explored. Plant growth-promoting traits of isolates were also analyzed. These isolates were found to produce siderophores and enzymes such as 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and aid in solubilization of mineral nutrients and modulate plant growth and development. Based on the presence of multiple plant growth-promoting traits, isolates were selected for molecular characterization and inoculation studies. Altogether, 58 isolates were obtained and 20% of them were able to tolerate Cd up to 400 ppm. The sequence analysis of the 16S rRNA genes indicates that the isolates belong to the phylum Firmicutes. Bacillus sp. along with mycorrhizae inoculation significantly improves the growth, the activity of antioxidants enzymes, and the Cd uptake in A. donax than Bacillus alone. Highly significant correlations were observed between Cd uptake, enzymatic activities, and plant growth characteristics at 1% level of significance. The synergistic interaction effect between these organisms helps to alleviate Cd effects on soil. Heavy metal-tolerant isolate along with arbuscular mycorrhizae (AM) could be used to improve the phytoremedial potential of plants.

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Unit level linear mixed models are often used in small area estimation (SAE), and the empirical best linear unbiased prediction (EBLUP) is widely used for the estimation of small area means under such models. However, EBLUP requires population level auxiliary data, atleast area specific aggregated values. Sometimes population level auxiliary data is either not available or not consistent with the survey data. We describe a SAE method that uses estimated population auxiliary information. Empirical results show that proposed method for SAE produces an efficient set of small area estimates.

Smallflower umbrella sedge is one of the problematic weeds in direct-seeded rice in India. Bispyribac-sodium (acetolactate synthase-inhibiting herbicide) is a commonly used in rice, but recently growers have reported lack of smallflower umbrella sedge control with this herbicide. An extensive survey was carried out in two rice growing states, Chhattisgarh and Kerala, where 53 putative bispyribac-sodium resistant (BR) biotypes were collected. Studies were conducted to confirm resistance to bispyribac-sodium and to test the efficacy of newly developed synthetic auxin herbicide florpyrauxifen-benzyl on putative BR biotypes. Whole-plant bioassay revealed that bispyribac-sodium is no longer effective. Of 53 putative BR biotypes, 17 biotypes survived recommended label rate of 25 g ai ha−1. Effective bispyribac-sodium rate required to control 50% of the plants in most of the BR biotypes (ED50) ranged from 19 to 96 g ha−1 whereas it was 10 g ha−1 in susceptible biotype. In two highly resistant biotypes, ED50 was beyond the maximum tested rate, 200 g ha−1. This suggests 2 to >20-fold resistance in BR biotypes. Acetolactate synthase (ALS) enzyme activity assay suggests altered target site as mechanism of resistance to bispyribac-sodium. This study confirms the first case of evolved resistance in smallflower umbrella sedge for bispyribac-sodium in India. However, the newly developed synthetic auxin, florpyrauxifen-benzyl effectively controlled all BR biotypes at the field use rate 31.25 g ae ha−1.

Rice-wheat is the major cropping system in the Indo-Gangetic plains and is also practiced on considerable area in Madhya Pradesh. Rice-wheat production system under conventional practices involves tedious and time-consuming methods of field preparation and weed management; increases cost of production, deteriorates soil fertility, and do not offer desired benefits for increasing the grain yields. In conventional agriculture, burning of crop leftover residue has become a major challenge that leads to loss of precious plant nutrients and deteriorates environmental quality. In order to mitigate these problems, technically-feasible, economically-viable and ecologically-permissible technologies need to be essentially adopted. A technology is required to facilitate timely sowing in standing stubbles, minimize weed infestation, lower cost of production, improve fertilizer/water-use efficiency and improve soil health. To reap the benefits of conservation agriculture (CA), studies were conducted at farmers' fields in rice-wheat-greengram cropping system in black-cotton soils in Madhya Pradesh for consecutive five years. Sowing was done with Happy Seeder. Emergence of weeds from upper soil surface was effectively controlled by herbicides. Results showed that the benefits of CA can well be harnessed in black-cotton soils with rice-wheat-greengram cropping system. Retention of crop residues on soil surface provided an effective mulch cover for nutrient and moisture conservation, temperature moderation and weed control.

Arsenic contamination in the rice agro-ecosystem, its consequent spread into the food chain, and its adverse impact are a global concern. However, assessment of the impact of arsenic contamination on the qualitative aspect of rice in the post-harvest phase has not been attempted. We laid down this particular experiment with the aim to assess how arsenic contamination influences the grain quality attributes and other elemental profiles of four popular rice varieties. The entire field study was conducted in the lower Indo-Gangetic plain from genotype (four) and environment (14 locations) interaction point of view, using the additive main effects and multiplicative interaction model. Our findings indicate that grain arsenic content can influence the grain quality attributes and other elemental profiles in a low to highly significant manner. Amylose content (r = 0.753), cooking time (r = 0.706), and gruel solid loss (r = 0.672, 0.721) were found to be positively correlated with grain arsenic content in high-yielding varieties. Noteworthy variations in micronutrient content like iron (6.63–9.23 mg kg−1), zinc (3.15–5.54 mg kg−1), and copper (2.04–3.86 mg kg−1) as well as soil properties are also visible. Moreover, indigenous rice varieties respond differently than high-yielding varieties. Besides these, a pronounced impact of gene/variety and environment interaction can be seen. The findings clearly indicate that the qualitative aspect of rice is also prone to As contamination. These outcomes will attract the attention of policy-makers and researchers to develop rice varieties that have desirable quality attributes appropriate for the arsenic-contaminated regions of the world for sustainable rice production.

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